Air Seal your attic before insulating

When one pops there head into the attic they may see something similar to the first picture & think that hey, I need some more insulation. I have lost count of how many people have simply seen something on TV or had an "energy audit" done where they recommended more insulation & I get called in later as they are still uncomfortable or having issues.
While I agree that the attic below definitely needs more insulation, there were a few things that need to be dealt with first. You see in order for insulation to work optimally it needs to be enclosed on all six sides which needless to say, doesn't fly when it comes to an attic. That is one reason why the R-Values are nearly doubled or tripled in the attic area when compared to walls. So what happens when you add air-leakage underneath – well it really cuts down on its performance.
While we had to remove the insulation in this area of the house,that is not always the case. If you don't have issues with mice, etc... you can simply move it out of the way & fix the problem areas. Some of the most common spots are;
· Wire & plumbing penetrations – use appropriate foam or caulk
· Drywall edges – foam or caulk
· Chases & soffits – foam board, drywall, or plywood to cap
· Around electrical boxes & exhaust fans - foam or caulk
· Stoves & furnace vents – this is a big "it depends" & sometimes is best left to a professional (especially for fireplaces), but fire rated caulk / foam & Roxul are commonly used
· Recessed lights – is it IC rated or Non-IC rated (
Is that the end... no as this attic had 2 bathroom vents that simply dumped their moisture in the attic, baffles that were non-existent and a few other items. Alas those are special issues that easily take up a full piece themselves.
This post is a modified version of you are considering or having this work done we encourage you to check out the full article & the rest of the series.

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      • Miriam I
        Miriam I Houston, TX
        on Feb 13, 2013

        Thank you for the great info, as always!

        • Duane
          Duane Warrenton, NC
          on Feb 18, 2013

          Have to deal with all the other ills first (wiring, rodents, vents ,etc.), but I went with sprayed foam on the underside of the roof. Have an oldddd house so got a solid 6 inches all over. Just no way to seal all of the leak points-balloon const walls etc. Sealed an unused chimney and used it as pipe and wire chase from basement for the new geothermal HVAC system snd new wiring to replace the knob and tube still in use! Old house woes, but at least you (mostly) know what to expect, unlike some of the shoddy new construction out there!